In recent years, technologies for wireless sensor networks have actively been developed. Wireless sensor networks are technologies for collecting people's behavior information or surrounding environment information, for example, by connecting wireless nodes in which wireless devices and sensor devices such as position sensors or temperature sensors are combined, to wireless networks. Wireless sensor networks are expected to be utilized in various fields such as monitoring systems and home automation. This is because advantages such as flexibility of reduction in cost, expansion of sensing ranges, and changes in networks can be expected when sensor networks are constructed with wireless communication.
Wireless sensor network systems can be considered to be designed variously depending on which is preferred among requests of applications to be applied. Examples of the requests include the amount of information of data and a direction of the data to be exchanged, a scale of the capacity of wireless nodes per base station, an extent of a communicable area, complexity of signal processing on a wireless node side, a transmission delay time, tolerance for mobility of a wireless node, reliability of data transmission, and addition of a base station or a wireless node. Here, since wireless nodes are assumed to be installed in various locations for a long time, the wireless nodes can necessarily operate with batteries for a long time to achieve low power consumption. Therefore, it is necessary to develop technologies for realizing low power consumption of the wireless nodes.
For example, the following Patent Literature 1 discloses a technology related to transmission power control performed for a reception side to measure an average reception bit error rate in call channels which are being used and increase or decrease transmission power of a transmission side to maintain an appropriate average reception bit error rate.